Radio frequency cable terminal



Sept. 19, 1939. w. Mesi-:R

RADIO FREQUENCY CABLE TERMINAL Filed dan. 21, 1956 @www Duro

law

INVENTOR.

WILHELM MOSER Ur s ATTORNEY.

Patented Sept. 19, 1939 UNITED STATES PATENT OFFICE RADIO FREQUENCY CABLE TERMINAL tion o f Germany Application January 21, 1936, Serial No. 60,055 In Germany January 24, 1935 3 Claims.

This invention relates to a new and novel terminal member particularly adapted to radiofrequency cables.

The object of the present invention is to irn- 5 prove the terminal members for concentric (coaxial) energy transmission lines for radio-frequency cables which serves for connecting a cable to a part of an apparatus, more particularly the combination of two such terminal pieces used for coupling together two radio-frequency cables to be joined.

Radio-frequency cables are extensively used in practice for connecting a radio-frequency generator or transmitter with a consuming or load device, or for joining an antenna with a receiver apparatus.

This invention will best be understood by referring to the accompanying drawing, in which:

Fig. 1a is a sectional view of one half of a ter- 20 minal piece;

Fig. 1b is a cross-sectional view of the radio frequency cable showing the concentrically arranged conductors;

Fig. 2 is a view of the complete terminal piece, partly in section and partly in elevation.

Radio-frequency cables consist mostly of an inner conductor in the form of a wire or cable or a plurality of. several electrically separated conductors which are concentrically or co-axially surrounded and enveloped by a tubular outer conductor, the inner and outer conductor being spaced a certain distance apart. The dielectric between the two conductors consists of air. In order to insure such spacing apart of the two conductors as shown in Fig. 1b there are employed beads, rings, or stays made of insulation material D. In order to provide external protection for the cable, the latter is in addition surrounded or sheathed by an insulating protective layer which is rmly brought upon the outer conductor.

The connection of such a cable with an apparatus or the uniting of two such cables is attended with certain difficulties, From a mechanical viewpoint, this connection should be stable, also replaceable, if possible. From an electrical angle, the connection or union should not occasion any essential change in the charac- 50 teristic impedance, in other words, the relation between the distributed capacity and the distributed inductance should be approximately preserved in order that no reiiections may be occasioned. In other words, a number oi constructional factors must be observed, while in addition a reliable conductive connection should be established.

A satisfactory solution of the problem is obtained by the terminal or coupler piece here disclosed which consists of the combination of vtwo such terminal pieces.

The terminal piece of this invention shown by Figs. 1a and 2 is designed for use on radio frequency cables which consist of a concentric or co-axial transmission line comprising a metallic inner conductor, outer conductor and an insulating protective layer placed thereover. The terminal member has this characteristic feature that a joint cap nut 4 is provided by means of which both the metallic outer conductor A of the energy transmission or radio frequency line as well as the insulation protective layer H are mechanically locked or xed at separate places and the outer conductor connected in a safe and reliable manner from an electric viewpoint.

The said end is secured by that the cap nut 4 serves to compress a pair of clamp or gripper pieces or jaws 2 which hold the insulation layer H, while a clamp ring 3, by the agency of the clamp jaws 2, is mechanically pressed firmly against the outer conductor A, the same insuring at the same time safe electrical connection between the outer conductor A, clamp ring 3 and a hollow metallic cone piece l which is attached to the part of the apparatus with which connection is to be made.

Another objqect of the invention is the combination of two terminal pieces to result in a coupling for two radio frequency cables which are to be joined.

For this purpose two terminal pieces are arranged so that one hollow metallic cone piece comes to be placed against the other. Mechanical and electrical connection between the said metallic cone pieces or between the outer conductors is comparatively simple; for instance, the two ends of the metallic cone pieces I are provided with opposite screw-threads and are then screwed together by the aid of a coupling ring R.

'I'he problem of uniting the inner conductors is attended with greater diiculties; in fact, this can not be accomplished directly. Forthe pur- -pose of establishing connection, members or parts of a plug device must be provided in both halves of the coupling means for the inner conductors.

In the cylindrical inside part of each metallic cone piece is provided, according to the invention, a plug or connector socket B at which the inner conductor of the corresponding cable ends. For

insuring electrical connection between the two sockets` serves a bilateral simple plug S. The material and construction of the plugs are so chosen i that intimate and permanent contactmaking will be produced by splitting the plugs to give good spring action.

Figs. 1a and 2 illustrate a terminal piece and one-half of a connector piece. T is the inner conductor, A is the outer conductor disposed concentrically or co-axially thereto; H is the insulating protective sheath or layer of a radio-frequency cable K, and D is the material used for spacing, such as rubber. A hollow metallic cone piece I serves both for establishing mechanical as well as electrical connection between the cable land an apparatus or another cable. For the mechanical and electrical connection of the metal cone I with cable K serve clamp jaw pieces 2 of conical form which rmly grip by their roughened portions r the protective sheath H of the cable K. Electric connection between the outer conductor A and the metallic cone piece I is eiected by the aid of a clamp ring 3 over which the outer conductor is crimped so as to secure safe contacting between the outer conductor and the metallic cone piece. In order to lock the assembly of the terminal piece, a cap nut 4 is employed which comes to bear rmly against the conical end of the clamp jaws 2 end thus forces the metallic cone piece I against the conical end of the clamp ring 3.

Fig. 2, by way of example, illustrates a complete coupler piece serving to unite two radio frequency cables.

Substantially, such a cable coupler consistslof the combination of two terminal pieces. Similar reference symbols refer to similar elements as in Figs. 1a and 1b.

For joining the outer conductors or the metallic cone pieces I serves, for instance, a coupler ring R. which presses the cone pieces I having opposite screw-threads against each other. For establishing connection between the inner conductors a number of additional parts are required, and these parts are required for both terminal pieces. However, for the purpose of proper understanding of the invention, it will be suicient to explain the disposition and the operation of the constituent parts merely by reference to the lower member of the coupling shown in section. Inside the cylindrical inner part of the metallic cone piece I is a bipartite or split insulator piece 5 which supports a socket B being undivided (not split) in longitudinal direction. The socket B is xed in the insulation piece 5 by means of riveting, crimping, or some other suitable manner known in the art. At its top end which is not enveloped by the insulation piece 5, the said bush B is provided with screw-thread. The inner conductor T of the cable K is pulled through the opening O in insulation part 5 and is clamped fast between the socket B and the washer disk 'I by the aid of an annular nut 6.

For mutual connection of the socket in both members of the coupling serves a bilateral plug piece. S made of some suitable material. The

.caracas plug prongs are either split or furnished with spring means in order that contacting may aiways be safe and satisfactory.

If desired, the cylindrical inner part of the metallic hollow cone I may be extended axially if for the accommodation of the socket and the plug more room is required.

The basic idea of the invention is not connned to the exemplified embodiments here shown.

Having thus described my invention, what I claim is:

1. In combination a cable comprising a tubular conductor and an outer protective sheath covering said conductor; a terminal for said cable, said terminal comprising a metallic terminal member located at one end of said tubular conductor, said metallic terminal member having at least one end hollowed out in the forml of a cone, a clamp ring located within the hollowed out cone portion of said terminal member for clamping said tubular conductor to the inside wall thereof, a plurality of clamp jaws adjacent said clamp ring and surrounding an end of said protective sheath, and a clamp nut for simultaneously compressing said clamp jaw on said protective sheath and clamping said clamp ring against said tubular conductor.

2. In combination a cable comprising a tubular conductor and an outer protective sheath covering said conductor; a terminal for said cable, said terminal comprising a metallic terminal member located at one end of said tubular conductor, said metallic terminal member having at least one end hollowed out in the form of a cone, a clamp ring located within the hollowed out cone portion of said terminal member, one end of said conductor crimped over said clamp ring whereby said tubular conductor is clamped to the inside Wall of said terminal member, a plurality of clamp jaws adjacent said clamp ring and surrounding an end of said protective sheath, and a clamp nut for simultaneously compressing said clamp jaws on said protective sheath and clamping said clamp ring against said tubular conductor.

3. In combination a cable comprising concentrically arranged inner and outer conductors, a protective sheath covering said outer conductor; a terminal for said cable, said terminal comprising a metallic terminal member located at one end of said outer conductor, said metallic terminal member having at least one end hollowed out in the form of a cone, a clamp ring located within the hollowed out cone portion of said terminal member for clamping said outer conductor to the inside Wall thereof, a plurality of clamp jaws adjacent said clamp 'ring and surrounding an end of said protective sheath, a clamp nut for simultaneously compressing said clamp jaws on said protective sheath and clamping said clamp ring against said outer conductor, and an insulating sleeve located within said terminal member and above said clamp ring for retaining connecting means for said inner conductor.

WILHELM MOSER. 

